Of course, I cannot find the reference right now, but I happened across the web page of an a/c shop owner one time. Among other topics, he discussed flushing systems. His shop generally used mineral spirits, though he said lacquer thinner was a fine choice as well. The main difference being mineral spirits are ~$3/gallon, while lacquer thinner is twice that, but more volatile.

My opinion is that it's not necessary to blow air through the system to dry it out. Remember, when it is pumped down, any remaining solvent is going to boil out in very short order. Any half decent vacuum pump will pull the system down to the point where water boils at -5F, let alone volatile solvents like lacquer thinner or mineral spirits.

When cleaning up my 124 after a seized compressor I flushed the system and blew out the components just until the exiting air no longer felt wet with solvent. Reassembled, pumped down for about an hour, and all has been well ever since.